检查数组中的值

How do i correct my code ..i would like to check a value if is in array

$years[] = ''.$myyear.'';
$years_array = "array('" . implode( "','", $years) . "');";

if (in_array("2017", $years_array)) 

{
//do this
}

else

{
//do this
}

Your in_array with if clause looks fine, but year_array is wrong (which is string not array)

You can define year_array simply like below

$years_array = array(2015,2016,2017,2018);

OR

// Define array
$years_array = array();

// Add elements to array
$years_array[]  = 2015;
$years_array[]  = 2016;
$years_array[] = 2017;

In case if you have list of years as string separated by comma, then you can create array using explode() function like below

// this is string
$year_string = '2015,2016,2017,2018';

// this is array
$year_array  = explode(',', $year_string);

// print string 
print $year_string.PHP_EOL;

// print the contents of array
print_r($year_array);

meanwhile you can read more about arrays from here